JPH03118425A - Photometric sensor - Google Patents

Abstract

PURPOSE:To correctly detect a photometric output by using a photoelectric converting device of a photodetecting part which is capable of reading an image signal without breaking, so that the image signal is read without being broken. CONSTITUTION:Photoelectric converting elements that can be read nondestructively are arranged in a two-dimensional matrix in a photodetecting part 1. The elements are scanned and read by a vertical and a horizontal scanning circuits 2, 4 according to an X-Y address method. In the circuit 2, the photoelectric converting elements arranged in a lateral direction of the photodetecting part 1 are sequentially scanned by vertical scanning pulses. Then, in a reading circuit 3, image signals in each lateral array of the photoelectric converting elements which are sequentially scanned by vertical scanning pulses are read out nondestructively by horizontal scanning pulses from the circuit 4. As a result, the image signals are output as a photometric output Vout to an output line 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a method in which the number of signal lines and the area of the insensitive region do not depend on the number of divisions of the light receiving section, and each light receiving element of the divided light receiving section The present invention relates to a photometric sensor that can detect changes in the amount of irradiated light in real time.

[Conventional technology]

BACKGROUND ART Conventionally, when photographing images such as microscopic images with a camera, it has been widely practiced to use a photodiode as a photometric element and determine the exposure time of the camera based on its output. That is, as shown in FIG. 4, the photocurrent of the photodiode 101 for photometry is accumulated in the capacitor 102 and inputted to the operational amplifier 103, and the output of the operational amplifier 103 is . As shown in Fig. 4), when the exposure amount reaches a predetermined value □ corresponding to the appropriate exposure amount of the camera, the exposure of the camera is terminated. In the fourth diagram, 104 is a reset transistor for resetting the accumulated charge of the capacitor 102, and a reset pulse φ shown in FIG. 4 (81) is applied to its gate.

Furthermore, the exposure of the camera is also adjusted to a certain narrow range within the field of view of a microscope or the like.

In order to adjust the exposure to a narrow area within the field of view, it is necessary to divide the area and perform photometry, but in this case, the light receiving element such as a photodiode must be divided into two or four parts on the same semiconductor substrate. Split sensors are widely used.

However, in order to photometer a part of a certain area with higher accuracy, it is necessary to increase the number of divisions so that photometry of the area corresponding to that part can be obtained. In order to meet such demands, photodiode arrays in which light receiving elements are arranged in a two-dimensional matrix are used.

[Problem to be solved by the invention]

However, as described above, if the number of divisions is increased and the number of light receiving elements is increased in order to accurately photometer a part of the area, the number of signal lines will increase. For example 16
When 16 photodiode plays are used, the number of signal lines becomes 256, and a complicated and expensive signal processing circuit is required for signal processing.

Furthermore, since the signal line passes between the divided light receiving elements, the insensitive area also increases with the number of divisions.

The present invention was made in order to solve the above-mentioned problems in conventional photometric sensors, and the number of signal lines and the area of the insensitive area do not depend on the number of divisions of the light receiving section, and the number of signal lines and the area of the insensitive area do not depend on the number of divided light receiving sections. It is an object of the present invention to provide a photometric sensor that can detect changes in the amount of light irradiated to each light receiving element almost in real time.

[Means and effects for solving the problems] In order to solve the above problems, the present invention provides a light receiving section in which non-destructively readable photoelectric conversion elements are arranged in a matrix, and each photoelectric conversion element in the light receiving section. A photometric sensor is constructed using a solid-state imaging device including a readout circuit that nondestructively reads out pixel signals using an X-Y address method and a control circuit that controls the readout.

In the photometric sensor configured in this way, the pixel signals of each photoelectric conversion element in the light receiving section are sequentially read out by the readout circuit using an x-y address method, so the signal line and insensitive area are used for photoelectric conversion. It does not depend on the number of elements, and therefore the increase in signal lines and insensitive areas can be suppressed. In addition, since the pixel signal of each photoelectric conversion element is configured to be read out non-destructively, it is read out repeatedly until the desired photometric output is obtained, and therefore the desired photometric output can be easily and accurately detected. It is also possible to measure changes in the amount of irradiated light.

〔Example〕

Examples will be described below. First, the basic configuration of the photometric sensor according to the present invention will be explained based on the conceptual diagram shown in FIG. In the first diagram, 1 is a light receiving section, in which nondestructively readable photoelectric conversion elements are arranged in a two-dimensional matrix, and each element is scanned and read out using an X-Y address method using horizontal and vertical scanning circuits. It is configured. Reference numeral 2 denotes a vertical scanning circuit, which sequentially scans the photoelectric conversion elements arranged in the horizontal direction of the light receiving section 1 by vertical scanning pulses output from the vertical scanning circuit. Reference numeral 3 denotes a readout circuit which non-destructively reads out the pixel signals of the photoelectric conversion element arrays arranged in the horizontal direction which are sequentially scanned by the vertical scanning pulses using the horizontal scanning pulses from the horizontal scanning circuit 4, and outputs the readout circuits. Photometric output on line 5 ■. . .

This is what is output as.

FIG. 1B) shows the reset pulse φ applied to reset the light receiving section 1 and the photometric output ■ of the output line 5.

. , the photoelectric charge accumulation state starts in the light receiving section 1 after the reset pulse φ is applied, and non-destructive readout is repeated until the next reset pulse φ is applied, resulting in a photometric output ■. , is outputted gradually increasing.

In this case, the photoelectric conversion element constituting one pixel has the following formula: t S & 11 $L = (NH/ f + t IL
) - Read out at intervals of Nv.

For example, NM=Nv=16. f=1 (MHz), tll
+-=31 μs), then t in. L, = 304t
It becomes μs1. That is, the amount of exposure applied to each pixel can be detected every 304 [t1s].

The output of the photometric sensor is an integral quantity, and corresponds to the amount of light irradiated by the reading time of the Habo sensor. By taking out the reading interval ts□11911
It is also possible to determine the change in the amount of light for each time, which makes it possible to not only control the exposure of the camera but also measure changes in the subject.

Next, specific examples of the present invention will be described.

FIG. 2 is a circuit diagram of an embodiment of a photometric sensor according to the present invention. In the figure, reference numeral 11 denotes a light receiving section, and a non-destructively readable photoelectric conversion element constituting this light receiving section 11 constitutes a pixel in a solid-state imaging device shown in, for example, Japanese Patent Laid-Open No. 63-33075. Static Induction Transistor
sistor (hereinafter abbreviated as SIT) is used. In this embodiment, the light receiving section 11 is divided into nine parts, and each pixel S I Tl1-11.11-12.11-13°11-21. . . . 11-33 are arranged in a 3×3 matrix.

The sources of the SITs arranged in the vertical direction are commonly connected to the vertical signal lines 12-1.12-2.12-3,
The gates of the SITs arranged in the horizontal direction are commonly connected to the row lines 13-1.13-2.13-3 via capacitors. In this embodiment, there are three vertical signal lines, and it can be seen that it does not depend on the number of divisions of the light receiving section. Note that each drain of each pixel SIT is commonly connected to a power source (not shown).

The vertical signal line 12-1.12-2.12-3 passes through the drain-source path of the transfer transistor lower I+ Qtz, QT3, and then connects to the storage capacitor C+, Cz, C.
x and drive transistor Qn + + Q o
Connected to the gates of z r Q o 3, respectively, and transfer transistors Q↑l+ QTz.

A transfer pulse φi is commonly applied to each gate of Qtz. Also, drive transistor Qn++Qaz+Q o
The drain of 3 is the power supply■. . are commonly connected to and their sources are the horizontal selection switch transistors Q! ＋l
+Q s z +Q s 3 to the output line 14 . Switch transistor Q 3++
Each gate of Qiz and Qsy is connected to a horizontal scanning circuit 15 to receive a horizontal scanning pulse φ.

Apply φ8□ and φ0.

Further, the drive transistor Qn++Qot+(L
z and switch transistor Q 5L+ Qszr
A reset transistor Q□+ is connected to Qss.
QR2°Ql13 are connected respectively, and the reset transistors Q1. A reset pulse φ7 is commonly applied to each gate of Q- and Q-1.

Further, a load resistor RL and an output line reset transistor Q*v are connected in parallel to the output line 14, and an output line reset pulse φ is applied to the reset transistors Q and lv.

The pixel signals stored in the storage capacitors C+, Ct, and Cs are transferred to the drive transistor Qo +
+ Q o z r Q D! and switch transistor Q! 1 +Q SKI Q10 and a source follower circuit composed of a load resistor R1.

On the other hand, the row lines 13-1.13-2.13-3 are connected to the vertical scanning circuit 16, and the vertical scanning pulse φVI+φ
vz and φv3 are applied, and the gate of each pixel SIT is controlled by this vertical scanning pulse at the time of readout and reset. Furthermore, the vertical signal line 12-1゜1
2-2.12-3 Transfer transistor lower I+
Q? ! The end opposite to the side connected to +Qts is a vertical signal line reset transistor Q*s I
rQ R3Z IQ■, and is grounded through the gates of these reset transistors, and a vertical signal line reset pulse φ pulse is commonly applied to each gate of these reset transistors. and the transfer transistor Qt + + Q
T t + Q t! , storage capacitor C,,C
,,C,,Drive transistor Qn Ir Q
Dt + QD! , switch transistor Qs
The readout circuit 17 is composed of r + Q 32 + Q s s and the reset transistors Q II + Q, z, Q, .

Next, the operation of the photometric sensor configured as described above will be explained based on the timing of each pulse and an example of the photometric output V0□ shown in FIG. In Figure 3, φVl+φ9□, φ1
．． is a vertical scanning pulse from the vertical scanning circuit 16, which controls the gate potential of each pixel SIT during reading and resetting via a capacitor. First, the vertical scanning pulse φv1 is applied to the pixel SIT column in the first row. Focusing on this, the reading of the pixel signal of the pixel SIT in the first row of the light receiving section 11 will be explained.

During periods t and t2, the vertical scanning pulse φv1 causes the pixels in the first row S I Tl1-11.11-12.11
A reset pulse is applied to each gate of -13. Also, during this period, the transfer pulse φd, the lyse throat pulse φXI
+Vertical signal line reset pulse φ8. becomes “H” level, and the transfer transistors Qt=, Q? ! , 9-3, reset transistor Q * I + Q * z,
Q +13, vertical signal line reset transistor Q *
s + + Q * s z + Q * 33
are respectively turned on, and the pixel S I Tl1-11.1
1-12゜11-13 and storage capacitor C,,C-
, Cx force < 1 is set. Next, at time L2, the vertical scanning pulse φV++$ multi-transmission pulse φ, and the resetting pulse φ.

When becomes “Level,” the pixel S I Tl1-11.11
12, 11-13 start optical integration.

Next, when the period reaches ~t4, the pixel 5ITll in the first row
-11, 11-12, 11-13 gates are read from the vertical scanning circuit 16 with vertical scanning 1<)res φv
+ is applied. Also, during this period, transfer
(“H” level, vertical signal line reset Hals φlIS
The transfer transistor Q r +
.

Since Qrt+QTs is turned on, pixel S I Tl1
The pixel signals of -11°11-12, 11-13 are transferred to the storage canomers C1C1 and C3 via the transfer transistors Qt+ and 'Qtz+QT3, and are stored therein. And it's time.

Transfer transistor Q? + + Qt
Even after z + Q r z is turned off, each pixel signal is connected to the capacitor CI.

It is held in Ct and Cx. After that, the horizontal scanning pulse φH++ φH2+ φ113 from the horizontal scanning circuit 15
and switch transistor Qs + + Q s z
+ Q s s are turned on sequentially, so that the storage capacitors c,, ct, and c.

Each pixel signal held in is sequentially read out to the output line 14 via the drive transistors QoI+Qnz+QoS, and the photometric output ■. , is output as .

After that, pixel S I Tl1-11.11-12.11
-13 cents is not performed, and the second reading is performed non-destructively during the period from 13 to t14. The pixel signal read during this period corresponds to the optical integration period from time L2 to time tri. Then do the same,
The third reading is performed non-destructively during the period t+s""'=tt&.

Pixel S I Tl1-21.11 on the second row of the light receiving section 11
-22°11-23 and 3rd row pixel S I Tl1-
Regarding 31.11-32.11-33, similarly to the readout operation for the pixels S I Tl1-11.11-12 and 11-13 in the first row, the periods t and ~Li
The period t is also ~t. The pixels S in the second and third rows in
IT reset operation is performed, period t, ~L8+period t
, ~t+z, the first read operation of the pixels SIT in the second and third rows is performed, respectively. Even after the first read operation, the second and subsequent read operations are performed without performing a reset operation, similar to the pixel SIT in the first row.

As described above, by using non-destructive readout, pixel signals can be read out repeatedly until the desired photometric output is obtained, and that photometric output is not only used to control the camera's exposure, but also used to detect light from the subject. It is also possible to measure changes in the amount of light in almost real time.

In the above embodiment, an SIT was used as the photoelectric conversion element constituting the light receiving section, but the photoelectric conversion element may be, for example, a CMD (charge modulation device).
Any element that can be read non-destructively, such as a modulation device, can be used.

Further, in the above embodiment, as a pixel signal readout method,
Although a method of sequentially reading out pixel signals using a shift register has been shown, the method is not limited to this method, and a method of using a decoder etc. to extract only the pixel signal of a desired pixel, a method of combining a shift register and a decoder, etc. can also be used. I can do it.

[Effects of the Invention] As described above based on the embodiments, according to the present invention, the pixel signal of each photoelectric conversion element of the light receiving section is configured to be read out by the readout circuit using the X-Y address method. Therefore, the number of signal lines and insensitive areas does not depend on the number of photoelectric conversion elements, and their increase can be suppressed. In addition, since the pixel signal is read out non-destructively using a photoelectric conversion element that can be read out non-destructively, reading is repeated until the desired photometric output is obtained, and the desired photometric output can be easily and accurately detected. It is also possible to easily measure changes in the amount of light emitted from the subject.

[Brief explanation of drawings]

FIG. 18 is a conceptual diagram showing the basic configuration of the photometric sensor according to the present invention, FIG. 1 (old) is a diagram showing an example of the reset pulse and photometric output of the photometric sensor shown in FIG. teeth,
FIG. 3 is a circuit configuration diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing an example of the timing of each pulse and photometric output to explain the operation of the photometric sensor shown in FIG. FIG. 4 is a diagram showing an example of the configuration of a photometric sensor (Bl is a diagram showing a reset pulse for its operation and its photometric output. In the figure, 1.11 is a light receiving section, and 2.16 is a vertical scanning circuit. , 3, 17 are readout circuits, 4, 15 are horizontal scanning circuits, 5.14 are output lines, 11-11.11-12.
...11-33 is pixel SIT, 12-1.
12-2.12-3 is a vertical signal line, 13-1.13-2
．． 13-3 is a row line, Q, , Q, □Q, is a multi-transmission transistor, Q n 1. Qoz,
Q D 3 is a drive transistor, QR + +
Q! 12, Q13 are reset transistors, Qs++Qsz+Qs3 are horizontal selection switch transistors, Q□+, Q
@S! . Q RS 3 is a vertical signal line reset transistor, C
3°C2°C1 represents a storage capacitor.

Claims (1)

[Claims] 1. A light receiving section in which non-destructively readable photoelectric conversion elements are arranged in a matrix, a readout circuit that non-destructively reads out pixel signals of each photoelectric conversion element of the light receiving section using an X-Y address method, and a readout circuit that controls the readout. A photometric sensor using a solid-state imaging device consisting of a control circuit.